Timber Framers Guild

Overhang on Kingpost Truss entryway

Posted By: JonS

Overhang on Kingpost Truss entryway - 09/15/15 01:04 PM

hi all,
I'm designing a small entryway (8' span, bents 6' apart) with two kingpost trusses, and wondering what is the simplest way to achieve an overhang? Can I just move the the posts inside the ends of the bottom chord by a foot?

I've seen the trusses that have the rafter passing by, and the bottom chord tenons into it, but it would seem to me that the peg on the chord tenon would be doing lots of work there where in a classic truss the rafter foot has a positive bearing on the mortise end in the chord....are these trusses sound?

Thanks for any insights you can provide.
Jon Santiago
Posted By: Jay White Cloud

Re: Overhang on Kingpost Truss entryway - 09/15/15 01:38 PM

Hello Jon,

It greatly depends, in this case, as the diminutive size gives you great flexibility, whether you are going for the more "European Old World" look with actual functioning "King Post" design parameters with oblique bracing all around.

or

A more contemporary modern and/or "Asian" post and lintel aesthetic. With this later form in design (similar to an "Engwa-Doma" entry area in Japan) the rafter "tails can extend quite a fair distance past the "rafter plate" and the "lower cord" if one is part of the design. Then the "King" carries the ridge beam, and may or may not act as a "true truss" in some of these designs unless there is "pass through" tenons and wedging and/or some other "pass through" beam work such as " Nuki ."

Good luck and picture, diagrams would be helpful as you seek deeper advice/guidance...

Regards,

j
Posted By: TIMBEAL

Re: Overhang on Kingpost Truss entryway - 09/15/15 04:46 PM

Pictures are always nice, here is a video of a kp truss with the rafters held in from the ends to accommodate the purlins lodged on top of the rafters. You could incorporate something like this.https://www.youtube.com/watch?v=NLD8-CEmTLE
Posted By: TIMBEAL

Re: Overhang on Kingpost Truss entryway - 09/15/15 04:47 PM

https://www.youtube.com/watch?v=NLD8-CEmTLE
Posted By: timberwrestler

Re: Overhang on Kingpost Truss entryway - 09/17/15 12:48 PM

Sure you can move the posts in. Especially with it being so small.
Posted By: JonS

Re: Overhang on Kingpost Truss entryway - 09/22/15 02:43 AM

thanks for the responses! still curious to hear commentary about modified king post trusses where the rafter passes the tie and the tie tenons into rafter instead of the other way around...i think called "raised chord kp truss"? is there a tradition behind these or is it modern aesthetic flourish? in these cases do people cut the back of the tie tenon square, rather than diagonal as in a brace, so that the thrust of the rafter bears on something more than pegs?
Posted By: Jim Rogers

Re: Overhang on Kingpost Truss entryway - 09/22/15 12:03 PM

Are you going to use planned on all four sizes stock or rough sawn timbers?

Jim Rogers
Posted By: Roger Nair

Re: Overhang on Kingpost Truss entryway - 09/22/15 11:56 PM

Since the span is short and the load small, I feel that a wood joinery solution will be in reach, with no resort to metallic connectors. I would use a centered wedged half-dovetail full length tenon as my tie joint approach. Seasoned wood will be most preferred for tie chord and wedges.
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